Arrangement for the automatic reg



Sept. 25, 1934. g RISZDORFER 1,974,433

ARRANGEMENT FOR THE AUTOMATIC REGULATION OF THE LENGTH OF TIME OF EXPOSURE IN TAKING PHOTOGRAPHIC PICTURES Filed 0G1,- 23, 1930 4 Sheets-Sheet l Se t.-25, 1934. E, RISZDQRFER 1,974,433

ARRANGEMENT FOR THE AUTOMATIC REGULATION OF THE LENGTH OF TIME OF EXPOSURE IN TAKING PHOTOGRAPHIC PICTURES Filed OOC 23, 1930 4 Sheets-Sheet 2 Inventor:

Sept. 25, 1934. E. RISZDORFER ARRANGEMENT FOR THE AUTOMATIC REGULATION OF THE LENGTH OF TIME OF EXPOSURE IN TAKING PHOTOGRAPHIC PICTURES Filed Oct. 23, 1930 4 Sheets-Sheet 3 56 U my. 5 56 Sept, 25, 1934-. E RISZDQRFER 1,974,433 ARRANGEMENT FOR THE AUTOMATIC REGULATION OF THE LENGTH OF TIME OF EXPOSURE IN TAKING PHOTOGRAPHIC PICTURES Filed 001.. 23, 1930 4 Sheets-Sheet 4 Patented Sept. .25, 1934 PATENT OFFICE ARRANGEMENT FOR THE AUTOMATIC REG-- ULATION OF THE. LENGTH OF TIME OF EXPOSURE IN TAKING PHOTOGRAPHIC PICTURES Edmond Riszdori'er, Budapest, Hungary Application October 23, 1930, Serial No. 490,786

2 Claims.

The invention relates to an arrangement for the automatic regulation of the length of time of exposure in taking photographic pictures, for

' which purpose a photo-cell is employed.

According to the invention resistances are provided in the circuit operating the automatic control of the object lens shutter or respectively of the diaphragm, one of which resistances is positively connected with the diaphragm or respectively with the shutter, such diaphragm or respectively shutter being adjustable by hand, whilst a second resistance is adjusted so as to suit the degree of sensitivity or the photographic plate and a further number-of resistances serve to eifect the necessary final adjustments.-

In the accompanying drawings like characters of reference indicate like parts in the several views and I Figure 1 is a perspective view, partly broken away, showinga camera equipped with one form of the invention.

Figure 2 is a wiring diagram for the inventio as disclosed in Figure '1.

Figure 3 is a perspective view, partly broken 2 away, showing a second form of the invention.

Figure 4 is a detail view, partly in section, of certain elementsused in the form shown in Figure 3.

Figure 5 he diagrammatic view of one arrangement of the device as shown in Figure 3.

Figure 6 is adiagrammatic 'view showing a somewhat different arrangement of the parts of Figure 3.

Figure '1 is a view similar to Figure 1 but showing a further modification of'the invention.

. Figure 8 is a diagrammatic view .of the parts shown in Figure 7.

Figure 9 is a view similar to Figure l and showing a fourth form of the invention.

Figure 10 is a diagrammatic view of the form shown in Figure 9.

In Figure 1, 11 is the casing of the photographic camera in which the object lens with the custom'ary shutter and the casing 12 of the latter is are housed. 13 is the usual regulating disk tor the shutter speed and 14 the usual releasing lever. Arranged in the camera is a light sensitive cell REISSUED sistance 25 is positively connected with the disk 13 for the. regulation of the shutter speed. The sliding contacts 27 and 28 of the resistances 24 and 23 are regulated by means of handles 29 and 30. The value of resistance that has been connected is shown by the scales 31 and 32. The arcuate armature 33 of the magnet 22 is carried by a disk 35 rotatably mounted on the shaft 34. Disposed in the groove 36 of the disk 35 is a thread 37 which is connected to the lever 39 66 which regulates the diaphragm 38 (Fig. 2) and which acts to operate this lever, the action of the armature being resisted by. the spring 40. Before exposure, resistance 23 is regulated according to the light sensitiveness of the emulsion used. for 70 the purpose. For this purpose, the scale 31 is preferably graduated according to the Scheiner- Graden scale or according to some other suitable scale, in such fashion that when a settingis made for increased light sensitiveness, there will be less to resistance, and that when a setting is made for reduced light sensitiveness, there will be more resistance (23) in the circuit of the cell 15.. After that, the desired shutter speed is regulated by means of disk 13 whereby, because of the autoso matic carrying of! of contact 26 proportionately more resistance 25 will be in the circuit of the cell 15 at high speeds and proportionately less resistance 25 at low speeds. The intensity of the current which then flows through the circuit coras responds to the resistances that are connected, which current then regulates the disk 35 of the rotating magnet 22 according to its strength. The smaller the lightsensitiveness of the emulsionand the larger the shutter speed that has been set, the larger will be the resistance and the smaller will be the current in circuit 41 and so much less will the diaphragm be contracted by the pull of 3'1. The larger the light sensitiveness and the smaller the shutter speed, the smaller as will be the resistance and the stronger will be the current in circuit 41 and the larger will be the contraction of the diaphragm through the pull of 37. Resistance 24 is s regulating resistance which should be connected at alltimes.

In the arrangement shown in Figure 3, which is well adapted for time exposures, 43 is the casing wherein is supported the mounting for the shutter, object lens 33 and the diaphragm, these parts being of usual construction. A photo-cell 45 is 103 arranged in the telescopic tube 48 and is exposed through the lens 47. Arranged behind this lens .47isanirisdiaphragm4'l'ssshcwninFigure 6. This diaphragm is opened and clmd by'mesns of a toothed wheel 48 and is completely shut before and after exposure. One of the terminals 49 of the photo-cell is connected with the source of current 51, by means of a wire 50. The other terminal 52 is connected in series with the armature 53, the regulatable resistance 54 and with the other pole of the source of current 51 through the electro-magnet 55 (Figures 4 and 6). 56 is a clock work mechanism arranged in the casing 48. This clock work mechanism operates the diaphragm 48 of thephoto-cell 45 by means of toothed wheels 57 and 58. The control for the mechanismisshowninFigure4. Tostartthe mechanism, the button'59 is pushed down- The button 59 carries a bolt 60. Figure 4 shows the button 59 in pressed-down position in full lines and raised in dotted lines. The bolt 60 of the button, after the resistance of the spring 61 has been overcome, moves into its pressed down position, in which it presses against pins 62 and 68, whose function will be hereinafter more fully explained. 64 is a locking pin which. through the pressure of the spring 65, is urged into locking position,

but which is retracted outofsuch locking po-- sition, when the current becomes sufiiciently strong by means of an electro-magnet 55 which acts upon the bolt head 66 functioning as an armature. The bolt 60 in its pressed-down position, closes the circuit 50 by means ofcontacts 6'7 and 68 and breaks the circuit by moving upwardly when locking bolt is being retracted.

Connected to the telescopic tube 46 of the photo-cell is a second telescopic tube 69. In other words, the slidable tube members 84 and of the said telescopic tubesare attached to each other. The two tubes are arranged parallel to each other. Telescopic tube 69'has at its front end a lens '10. In its back portion the telescopic tube 84 is provided with a small mirror '11 .and is connected to a slide '12 which is slidingly arranged on the outer wall of the camera. Disposed in a hole of the slide above the mirror is a search-lens 73. The slide '78 can be shifted in the direction of theaxls of the tube 69 with the result that the mirror 71 can be moved closer to or further away from the lens 70. The tube 85 of the photo-cell automatically participates in this shifting motion. The shifting is done by means of a pinion 74 which engages a rack 75.

The control device mounted on the casing 43 adjacent the slide 72 is, by means of the flexible shaft ,76, connected with the releasing mechanism of the shutter of the object lens. This release mechanism is of the usual type wherein the pressure of a button releases the shutter.

The tension of the spring of the mechanism 56 is regulated through turning of the knob 81. The pointer of the knob 81 moves over a scale 82.- Tensioning of the spring of the mechanism or clockwork controls the working speed of the clock work. The larger the opening width of the diaphragm (of object lens 83) used for the exposure the more the spring of the clock work will be tensioned. To facilitate the operation it is advisable to graduate the scale 82 in conformity with the opening diameters of thediaphragm to be selected.

The apparatus described in the present application is constructed for time exposures, i. e. particularly for use in studies, and operates as follows:

After the diaphragm of the object lens 88 has been set and the spring tensioned through turning the knob 81, the button 59 is pushed down, whereupon the stop "I7 of the bolt 60 forces the pin 62 against the spring 78 inthe direction of the arro'wrcausing thereby the lever '19 to swing to the left and to start clock work 56. when the bolt 60 continues its downward movement, the pin 68 is pushed by the stop I! against the spring 86 and is likewise forced to the left. The pin 68 actuates a flexible shaft 76 by means of which the shutter of the object lens is released. At the same time, the circuit 50 'is closed through contacts 67 and 68, and the clock work 56 begins to open, by means of toothed gear wheels 57, 58, 48,

the completely closed diaphragm of the object lens 47 of the cell. The more the diaphragm is opened the stronger will be the currentvwhich flows through the circuit 50 of the photo-cell.

When a predetermined strength of current is reached, the armature 66 is attracted by the magnet 55 and the bolt 60 is thereby released. The

latter, by means of the spring 61, is forced back into its dotted line position. At the same time.

the pin 63 is forced back to the right by spring 80 whereby the shutter of the camera is closed. And

also the pin 62 is forced back to the right by the spring '18, whereby the clockwork is stopped and the diaphragm of the object lens 47 of the cell is completely .closed. The resistance 54 serves to regulate the circuit 50.

In case of exposures in which the object to be photographed shows considerable differences in brightness the photo-cellshould be adjusted only to the dark portions of the picture. tubes 84, 85 should therefore be adjusted by means of the driver 74, 75 to reduce the angle of the picture until only the dark portions remain visible in the search lens '13. In this way the exposing time is lengthened. Less light will get into the cell, and the current in the circuit 50 will increase slower in intensity.

The element of the apparatus which is to be regulated automatically, for instance the diaphragm or the shutter of the object lens, may be controlled also by means of a special electric circuit, whereby such circuit is connected or disconnected by a relay actuated by the current of the light sensitive cell. The relay is so constructed that the regulating action forinstance the time of the actuation of the regulating mechanism, depends upon the intensity of the current of the cell, that is to say, upon the degree of brightness. Therelay is, therefore, provided with a contact element which is movably, for instance tumably, mounted, and which is moved in proportion to the intensity of the current of the cell. with the result that the turning of the contact increases 'in accordance with the intensity of the current of the cell, in a similar manner as this is the case in measuring instruments. The counter contact may either likewise be constructed as a movable contact or, under certain conditions, be of the stationary type as hereinafter described. It is important that the regulating action depends upon the degree of turning of the first contact, which moves in proportion to the intensity of the current of the cell. This interdependence is obtained bythe arrangement that this contact controls the circuit of the regulating mechanism. The regulating action, that is to say, the regulating mechanism, can either be started by hand, in which case it will be interrupted or arrested by the contact actuated by the current of the cell in a certain position (corre- 1 spending to the degree of brightnes) of the element to be regulated. Or the regulating action is started by this contact and interrupted after the element to be regulated has reached the desired position.

The pair of 105 Generally speaking, it can be said that, re-

gardless oi whetherthe regulating action has.

been started by the relay or by other means, the regulating is interrupted when the contact controlled by the current of. the cell has reached its outermost position corresponding to the intensity of the current and in this position produces a' ured from its starting position) according to the degree of intensity oi the current in the circuit oi the cell. The second contact, which is arranged in the path of the first mentioned contact, may be actuated by the regulating mechanism 'oi the element to be regulated, for instance by a clock work or an electro-motor which operates the diaphragm. The contact moved by the current of the cell takes up its position at a distance from its zero position which is proportionate to the intensity of the current of the cell. It is at this last mentioned position that the second contact which is actuated by the regulating mechanism meets the first contact which is moved by the current of the cell, whereupon the regulating action is interrupted.-

The second movable contact may also be constructed so that it is carried oil! by the first contact. The first movable contact is moved each time for a distance which is proportionate to the intensity of the current in the circuit of the cell. The contact with the second contact .is established at a predetermined minimum intensity of current, whereupon if the current or the cell further increases in intensity the second contact is taken along by the first contact, while at the same time the circuit remains closed. There now are several possibilities of controlling a regulating mechanism which is started through the establishment of contact between the two movable contacts in dependence upon the length of the path at which the first contact meets and carries oi! the second contact. Since, however, this path is eachtime proportionate to the intensity of the current of the relay it is quite possibleto also produce in this way an interdependence between the intensity of the current of the relay and the course of the started regulating action.

In this case the second movable contact maya be actuated by a driving mechanism, for instance a clockwork, would'be started through the establishment of :contact between the two contacts, and arrested after the contact has been broken. It is also quite possible to use an elecregulating m which is started through the establishment oi contact between the two contacts and which remains active as long as the contact exists. i.5"e. as long as the work ing circuit remains closed. -l"or actuation o! the element to be regulated, for instance the diaphragm, and for the actuation of the second contactacommondrivingmeanaiorinstance There also a clockwork may be used. This driving means remains active. during the time of contact, with the result that the element to be regulated is actuated-in proportion to the extent of the displacement of the contacts. Y

Another form of the arrangement would-.be to also provide the light sensitive cell with a diaphragm and to regulate this diaphragm as well as the diaphragm of the camera by a .common regulating mechanism which is controlled by the current of the cell, whereby the regulating action would start at an identical starting position, for instance the opened position. In an arrangement like this, the second contact of the relay is preferably a stationary one and so arranged that at a minimum intensity oi'thecurrent of the cell, predetermined through gauging, the contact is interrupted and-the regulating action arrested.

In the arrangements shown in Figs. 7 and 8, the current of the photo-cell 8'7, arranged in the casing 86 and upon which the light is cast through the lens 88, serves indirectly to regulate ,the diaphragm ring 101 of the object lens '89,

from its zero position in,the direction indicated by the arrow 95. This movement can take place over a scale 96. Contact 93 is arranged in a circuit 9'7, which is energized by a battery 98. The counter contact 99 is likewise a movable contact and is actuated by the regulating mechanism 100 of the diaphragm ring 101. The counter contact 99, like the contact 93, is shaped like a pointer, and contact between the two is established at the bent end 99'. The contacts 93 and 99, 99 are coaxially journaled. The regulating mechanism 100 is a clockworkm The clock work is controlled by a magnet 102, which acts upon the armature 103 controlling an arresting means. The arrangement is thus similar to that shown in Figure 4. Regulating mechanism 100 controls the diaphragm. 101 by means of toothed wheels 104 and 105. An observation window is indicated by the numeral, 106.

The-contact 93 is out of action in its end position at the left andthe contact 99 is out of action at its end position on the right. These end positions are shown in dotted lines in Figure 8. First, the cell 8'7 is erposed to the light whereupon contact 93 begins to move. The degree to which contact, 93 swings around; in other words, the position of contact 93, corresponds to the intensity of the-current of the cell. when the clockwork 100 isstartedbyhanditwillbegintoopenthe diaphragm ring 101 out of its completely closed position until the contact 99 reaches the contact 93. When the contacts meet the circuit 90 is closed, the magnet 102 acts and the clockwork or regulating mechanism l00 is arrested. ,The intenser the b the smaller the opening diameter or the diaphragm will be set, and vice versa.

Thet'mayalsobesuch thatthediaphragm is normally completely opened and thensteadily closed by the regulating mechanism. In this case both contacts are moved in the same di-- rection, i. e. counter contact 99 will follow the contact 93 after the latter has been displaced. The intenser the brightness the further the contact93willswingout,andthesmallertheopening In the forms 01 construction shown in Figures 0 and 10, two diaphragms have been provided. The diaphragm 107 o! the object lens 108 is for the exposure, whfle the diaphragm 100 regulates the cone or iightwhich is east through the object lens 110 into the cell 8'1. The regulating mechanism which controls both of the diaphragms consists of an electro-motor 111 and toothed-gear wheels 112. ilii'and 114. A relay, actuated by the circuit of the cell 87, has a movable contact us shaped like a pointer, and a stationary contact 116. The latter isarranged in the path of the contact 115 in aposition whose distance from the aero-position, shown in dotted lines, is empirically ascertained, but which may also be variable. The motor 111 is energized by a source of current 96. when not in operation, both diaphragms are completely open. when the circuit cell, is steadily reduced.

01' the cell is closed, the contact 115 engages the contact 116 with the result that the circuit 117 is closed. Then the motor 111 begins to opcrate and moves (by means of the toothed gear wheels 112. 118, and 114) both diaphragm 10'! and 109 in the direction of the arrows, that is, in closing direction, whereupon the supply of light to the cell. and accordingly also the current in the When the current in the circuit00 hasbeenreducedtosuch'anextent that the contact 115 swings away from the stationary contact 116, the regulating circuit 11'! is interrupted and the are not moved any further. Then the shutter of, the camera is released by hand and the plate exposed.

The invention includes still further regulating possibilities. The regulation. of the diaphragm can also be made to depend upon the setting or the shutter speed, or upon the s'ensitlveness oi the plate, in short, upon all those values which influence the time .0! exposure. For this purpose, the position of the contacts may be changed in such manner that contact between them will be established according to requirement after a more or less extended deflection. For instance, the starting position 01' the counter contact as shown lnl lgures'land9maybechangedandbemade to depend upon the sensitive'ness oi the light sensitive emulsion used, or from the speed of the shutter, or the like. There also might be arranged in the circuit of the photo-cell regulating resistances (asshown in Figure 1) which are controlled in dependence upon the said values.

1,974,488 diameterotthe diaphragmwiil-baandviceversa. In all oi the dacribed examples, the element toberegulatedhasbeenthediaphragmotthe object lens. However, the arrangement may just aswellbesuchthatthespeedremlato'rotthc shutter oi the object lens is influenced by the reguhting mechanism, in which case the ratio of gearing, the contact position, the resistance of thecircuit-oithecelLorthelike. willbechanged' in dependence upon the selected opening width or the diaphragm. Means, for instance resistances, might also bearranged in the circuit of the light sensitive cell oi. the forms oi. construction shown in Figures 7-10, which would change the intensity of current in this circuit according to the values not influenced-by the current of the cell, for instance according to the shutter speed when the diaphragm is regulated by the cell, or according to the diaphragm when the shutter speed is regulated by the cell, or according to the sensitiveness oi the plate, or mcording to the filters or the like that may be used.

I claim: v 1. The combination with a camera having a variable diaphragm, a shutter. and means to regulate the speed of said shutter; oi electro-magnetic means for regulating the extent of opening of the diaphragm, a light sensitive cell, asource 01 current, and means to connect the electro-magnetic means, cell and source of current in series, said connecting means including a variable resistance, and an operative connection between said resistance and the means to regulate the speed of the shutter.

2. The combination with a camera having a variable diaphragm. a shutter, and means to regulate the speed 01' said shutter; of electro-magnetic means for regulating the extent of opening oi the diaphragm, a light sensitive cell, a source of current, and means to connect the electromagnetic means, cell and source oi current in series, said connecting means including a variable resistance, and an operative connection between said resistance and the means to regulate the speed of the shutter, said connecting means further including a second manually controlled va-, riable resistance and a setting scale therefor arranged to indicate relative emulsion sensitivities.

EDMOND RISZDORFER. 25 

